Pisum Fulvum Research Articles

A hypervariable intron of the STAYGREEN locus provides excellent discrimination among Pisum fulvum accessions and reveals evidence for a relatively recent hybridization event with Pisum sativum.

An analysis of 82 non-synonymous Pisum fulvum accessions for sequence variation in a fragment of the STAYGREEN (SGR) locus revealed 57 alleles, most of which differed in indel structure. Eight additional P. fulvum accessions, each supposedly synonymous with a different accession of the initial group, were also analyzed. In every case the paired synonymous accessions possessed the same SGR sequence but varied slightly for a 6-trait morphological phenotype, indicating that SGR sequence is a much more reliable indicator of accession identity than is a morphological characterization. SGR sequence analysis confirmed our previous finding that P. fulvum accessions separate into two allele groups. This division was not supported by results of previous studies that were based on sequences distributed across the entire genome, suggesting that the division may have been produced by selection at a nearby locus and that the SGR phylogeny may not be good indicator of overall relationships within the species. One P. fulvum accession, PI 595941 (=JI1796), displayed an SGR sequence outside the variation typical of the species. Instead, its allele resembled alleles limited to a set of Pisum sativum landraces from the Middle East, suggesting hybridization between ancestors of PI 595941 and some primitive form of domesticated P. sativum. With one exception from the extreme northwest corner of Israel, P. fulvum accessions collected north of latitude 35.5° N were fixed for alleles from group A. These northern accessions also displayed greatly reduced SGR sequence diversity compared to group A accessions collected from other regions, suggesting that the northern populations may represent recent extensions of the range of the species. Group B accessions were distributed from Lake Tiberias south and were generally sympatric with the southern group A accessions. Although group B accessions occupied a smaller area than group A, the SGR sequence diversity in this group (28 alleles in 33 accessions) exceeded that for group A.

New Insights into Plastid and Mitochondria Evolution in Wild Peas (Pisum L.)

Plastids and mitochondria are organelles of plant cells with small genomes, which may exhibit discordant microevolution as we earlier revealed in pea crop wild relatives. We sequenced 22 plastid and mitochondrial genomes of Pisum sativum subsp. elatius and Pisum fulvum using Illumina platform, so that the updated sample comprised 64 accessions. Most wild peas from continental southern Europe and a single specimen from Morocco were found to share the same organellar genome constitution; four others, presumably hybrid constitutions, were revealed in Mediterranean islands and Athos Peninsula. A mitochondrial genome closely related to that of Pisum abyssinicum, from Yemen and Ethiopia, was unexpectedly found in an accession of P. sativum subsp. elatius from Israel, their plastid genomes being unrelated. Phylogenetic reconstructions based on plastid and mitochondrial genomes revealed different sets of wild peas to be most related to cultivated P. sativum subsp. sativum, making its wild progenitor and its origin area enigmatic. An accession of P. fulvum representing ‘fulvum-b’ branch, according to a nuclear marker, appeared in the same branch as other fulvum accessions in organellar trees. The results stress the complicated evolution and structure of genetic diversity of pea crop wild relatives.

Aphid Resistance in Pisum Affects the Feeding Behavior of Pea-Adapted and Non-Pea-Adapted Biotypes of Acyrthosiphon pisum Differently.

Simple SummaryResistance of a Pisum fulvum and five Pisum sativum genotypes to Acyrthosiphon pisum pea and alfalfa-adapted biotypes was evaluated by measuring aphid body mass, confirming the variable resistance level of these genotypes. The feeding behavior of the aphids on the Pisum genotypes was then examined by electropenetrography (EPG). The EPG results suggested that the resistance of Pisum genotypes to non-adapted A. pisum resides in mesophyll and phloem tissues while the resistance variation of P. sativum to pea adapted aphids may be influenced by the quality of phloem sap.Resistant genotypes of crops have emerged as an alternative and sustainable solution to pesticide use against pest insects. The resistance depends on the genetic diversity of the host plant and the pest species and can cause an alteration of the insect behavior. The aim of this work was to characterize the resistance level of different Pisum genotypes (one P. fulvum and five P. sativum genotypes) to two biotypes of the aphid Acyrthosiphon pisum, respectively adapted to pea and alfalfa, by measuring the individual aphid weight and analyzing aphid feeding behavior by electropenetrography (EPG). Aphid body mass was influenced by Pisum genotypes reflecting variation in their resistance level. P. fulvum was the most resistant to the A. pisum pea biotype (ArPo28 clone) and showed intermediate resistance to the A. pisum alfalfa biotype (LSR1 clone). The resistance levels of the five P. sativum genotypes to the two aphid biotypes were variable and more pronounced for the alfalfa biotype. EPG data showed that ArPo28 on P. fulvum and LSR1 on all the Pisum genotypes spent shorter time phloem feeding compared to ArPo28 on P. sativum genotypes, indicating that the resistance of Pisum genotypes to non-adapted A. pisum resides in mesophyll and phloem cells. In the meantime, ArPo28 on P. sativum genotypes with a different level of resistance spent a similar length of time phloem feeding, indicating that the quality of phloem sap of the resistance genotypes may not be optimal for the aphid. The study indicated that the resistance of Pisum genotypes to the two A. pisum biotypes involves different genetic factors and mechanisms that affect the aphid differently.

Prospects for the natural distribution of crop wild-relatives with limited adaptability: The case of the wild pea Pisum fulvum

Plant breeders and conservationist depend on knowledge about the genetic variation of their species of interest. Pisum fulvum, a wild relative of domesticated pea, has attracted attention as a genetic resource for crop improvement, yet little information about its diversity in the wild has been published hitherto. We sampled 15 populations of P. fulvum from Israeli natural habitats and conducted genotyping by sequencing to analyse their genetic diversity and adaptive state. We also attempted to evaluate the species past demography and the prospects of its future reaction to environmental changes. The results suggest that genetic diversity of P. fulvum is low to medium and is distributed between well diverged populations. Surprisingly, with 56 % in the total population the selfing rate was found to be significantly lower than expected from a species that is commonly assumed to be a predominant selfer. We found a strong genetic bottleneck during the last glacial period and only limited patterns of isolation by distance and environment, which explained 13 %–18 % of the genetic variation. Despite the weak signatures of genome-wide IBE, 1,354 markers were significantly correlated with environmental factors, 1,233 of which were located within known genes with a nonsynonymous to synonymous ratio of 0.382. Species distribution modelling depicted an ongoing fragmentation and decreased habitable area over the next 80 years under two different socio-economic pathways. Our results suggest that complex interactions of substantial drift and selection shaped the genome of P. fulvum. Climate changeis likely to cause further erosion of genetic diversity in P. fulvum. Systematic ex-situ conservation may be advisable to safeguard genetic variability for future utilization of this species.

Population genetic structure and classification of cultivated and wild pea (Pisum sp.) based on morphological traits and SSR markers

AbstractPea (Pisum sativum L.) is an important legume crop that is widely grown worldwide for human consumption and livestock feed. Despite extensive studies, the population genetic structure and classification of cultivated and wild pea (Pisum sp.) remain controversial. To characterize patterns of genetic and morphological variation and investigate the classification of Pisum, we conducted comprehensive population genetic analyses for 323 accessions from cultivated and wild pea, representing three species of Pisum and utilizing 34 morphological traits and 87 polymorphic simple sequence repeat markers. First, we identified three distinct genetic groups among all samples. Group I was primarily composed of Pisum fulvum, Pisum abyssinicum, and some wild P. sativum accessions, whereas Groups II and III consisted of the two genetic groups under P. sativum that represented different geographic distributions of cultivated pea. Analyses of morphological variation revealed significant differences among the three species. Second, among pea germplasms representing eight taxa of Pisum, P. fulvum and P. abyssinicum possessed unique genetic backgrounds and morphological characteristics, corroborating their independent species status. The intraspecific subdivisions of P. sativum described by some authors were not supported in this study, with the exception of several genotypes of P. sativum subsp. elatius that clustered with P. fulvum and P. abyssinicum. Finally, we confirmed that the Chinese pea germplasm was genetically distinct and could be divided into two genetic groups, each of which included both spring‐sowing and autumn‐sowing ecotypes. These results provide a robust foundation for understanding pea domestication and the utilization of wild genetic resources of pea.

Limited divergent adaptation despite a substantial environmental cline in wild pea.

Isolation by environment (IBE) is a widespread phenomenon in nature. It is commonly expected that the degree of difference among environments is proportional to the level of divergence between populations in their respective environments. It is therefore assumed that a species' genetic diversity displays a pattern of IBE in the presence of a strong environmental cline if gene flow does not mitigate isolation. We tested this common assumption by analysing the genetic diversity and demographic history of Pisum fulvum, which inhabits contrasting habitats in the southern Levant and is expected to display only minor migration rates between populations, making it an ideal test case. Ecogeographical and subpopulation structure were analysed and compared. The correlation of genetic with environmental distances was calculated to test the effect of isolation by distance and IBE and detect the main drivers of these effects. Historical effective population size was estimated using stairway plot. Limited overlap of ecogeographical and genetic clustering was observed, and correlation between genetic and environmental distances was statistically significant but small. We detected a sharp decline of effective population size during the last glacial period. The low degree of IBE may be the result of genetic drift due to a past bottleneck. Our findings contradict the expectation that strong environmental clines cause IBE in the absence of extensive gene flow.

Comparative androgenetic competence of various species and genotypes within the genus Pisum L.

In pea breeding is important to shorten the generation cycles to obtain homozygosity quickly. Doubled haploid technology is important to attain this purpose and androgenesis is the most promising tool for induction of haploids in legumes. Commercial pea varieties have been described as recalcitrant to this approach but very little is known regarding the androgenic competence of pea relatives. In this work, a comparative study of the androgenic response among different taxa of the genus Pisum was undertaken. We cultured anthers of 11 pea materials from the primary and secondary genepools under the same experimental conditions, and studied their competence to produce calli and plants in vitro. Significant differences were found in the percentage of callus and plant production between the different species and subspecies. The two wild forms Pisum fulvum Sibth. & Sm. and Pisum sativum subsp. elatius (Bieb.) Aschers. & Graebn. regenerated shoots from anther culture with the highest efficiency (67% and 38%, respectively), becoming potential sources of androgenic competence. Among the cultivated genotypes of P. sativum, the botanical variety arvense regenerated shoots with the highest percentage (40%) also being a good candidate to study androgenesis. The commercial varieties tested showed significant differences in the callus and plant production, with Primogenita (FCA-INTA) and B101 giving the best results although with low plant regeneration percentages (17% and 11%, respectively). P. fulvum, P. sativum subsp. elatius and P. sativum subsp sativum var arvense were identified as highly responsive to anther culture, useful to transfer androgenesis competence to recalcitrant commercial varieties. Within genus Pisum, the wild forms P. fulvum, P. sativum subspecies elatius and the cultivated variety arvense were identified as potential sources to introduce androgenesis competence into recalcitrant commercial varieties.

Environmental and genetic determinants of amphicarpy in Pisum fulvum, a wild relative of domesticated pea

Pisum fulvum is an annual legume native to Syria, Lebanon, Israel and Jordan. In certain locations, P. fulvum individuals were documented to display a reproductive dimorphism – amphicarpy, with both above and below ground flowers and pods. Herein we aimed to study the possible role of soil texture on amphicarpy in P. fulvum, to investigate the possible bio-climatic associations of P. fulvum amphicarpy and to identify genetic markers associated with this phenotype. A set of 127 germplasm accessions sampled across the Israeli distribution range of the species was phenotyped in two common garden nurseries. Land use and bioclimatic data were used to delineate the eco-geographic clustering of accession's sampling sites. Single nucleotide polymorphism (SNP) markers were employed in genome-wide association study to identify associated loci. Amphicarpy was subject to strong experimental site x genotype interaction with higher phenotypic expression in fine textured soil relative to sandy loam. Amphicarpy was more prevalent among accessions sampled in eastern Judea and Samaria and was weakly associated with early phenology and relatively modest above ground biomass production. Twelve SNP markers were significantly associated with amphicarpy, each explaining between 8 and 12 % of the phenotypic variation. In P. fulvum amphicarpy seems to be a polygenetic trait controlled by an array of genes that is likely to be affected by environmental stimuli. The probable selective advantage of the association between amphicarpy and early flowering is in line with its relative prevalence in drought prone territories subject to heavy grazing.

Reciprocal compatibility within the genus Pisum L. as studied in F1 hybrids. 3. Crosses involving P. abyssinicum A. Br.

A greenhouse experiment of crossing eight accessions of peas (Pisum L.), representing their different taxa and divergent lineages, with each other and to self has been carried out, aimed at evaluating reproductive barriers inside this genus which may be of importance for pre-breeding. The results of crosses involving the cultivated pea, P. sativum L. subsp. sativum, and Pisum fulvum Sibth. et Smith has been published earlier, while this paper presents those of crosses involving Pisum abyssinicum A. Br. (accession VIR2759 from Ethiopia). It was crossed, in both directions, with seven accessions representing P. fulvum (1 accession), P. sativum L. subsp. elatius (Bieb.) Schmalh. s.l. (5 accessions) and the cultivated pea, P. sativum subsp. sativum (1 accession). The average number of hybrid seeds per cross (crossing efficiency) was evaluated and the reciprocal F1 hybrids were analysed for pollen and seed fertility and some quantitative traits. Two crossing combinations produced no hybrid seeds. Male and female fertilities of F1 hybrids with P. abyssinicum were on average low but better than of the hybrids with P. fulvum analysed earlier. Both fertilities were on average better in hybrids with representatives of the evolutionary lineage AC of P. sativum than with those of the lineage B. In most cases differences in the fertilities were registered between reciprocal hybrid classes supposedly due to the conflict of the nucleus and plastids. Two hybrid classes produced no seeds. In one of them a hybrid plant was found which inherited paternal plastid (but maternal mitochondria); its male fertility was elevated to the level of the reciprocals but did not restore seed fertility. Surprisingly, the F1 hybrids of P. abyssinicum resulting from pollination by accession 721, a tall climber from Mt. Carmel, showed fully fertile pollen, indicating their relatedness. These data show that crossability of the Abyssinian pea with all other peas is very poor (with one exception in one direction only), supporting its specific status in frame of the biological species concept.

Relationships among cultivated peas and their wild relatives: Molecular and morphological characterization

This study was conducted to determine relationship between some wild pea accessions (Pisum fulvum L., P. abyssinicum L., P. sativum var. elatius), local varieties (P. sativum var. sativum L. and P. sativum var. arvense L.) and commercial varieties “Boogie” and “Rondo”. The genetic diversity was evaluated with 14 simple sequence repeat markers and 50 morphological characters. The results of morphology indicated that, genotypes showed a clustering pattern based on the taxonomic groups when considering only flower characters and all morphological characters. During the molecular study, a total of 48 alleles were obtained. Used all primers showed polymorphism in accessions. The number of alleles varied between 2 - 6 among 14 SSR loci revealing the polymorphism level of markers. Similarity coefficient (Dice’s) ranged from 0.100 to 0.800 with an average of 0.378. A dendrogram grouped the 15 genotypes into two main clusters. This information can be utilized for genetic analysis, genotype identification from different sources and development of improved germplasm.

Lectin from Pisum fulvum Seeds as in vitro Anticancer and Apoptotic Gene Regulator

The lectins are non-immune origin carbohydrate-binding proteins. Plant�s lectins are distributed in many species of medicinal plants, family Fabaceae. In this study the safety usage pattern of wild Pisum fulvum lectin was evaluated on different mammalian noncancerous cell types and the anticancer activity was examined on different cancer human cell lines: colorectal adenocarcinoma (Caco-2), hepatocellular carcinoma (HepG2), breast cancer cells (MCF7) and laryngeal carcinoma (Hep-2 cells). Moreover, both morphological and molecular evidence of apoptosis have been detected using both acridine orange/ethidium bromide (AO/EB) stain and RT-qPCR. The results revealed that IC50 of the wild lectin on the noncancerous cells ranged from 19.7 to 2.4 �g protein/mL. In addition, lectin was more potent against HepG2 cells than the other used cells, with inhibition percentages ranged from 68.45 to 90.98 and with cancer cell selectivity index ranged 3.5 to 28.14. The treatment showed 67.6% inhibition of BrdU incorporation in the proliferated hepatocellular carcinoma cells. Furthermore, HepG2-lectin treated cells showed obvious nuclear condensation after 48 h of treatment with ability to down-regulate the expression of BCL2 and BAX and to up-regulate the expression of Ikab gene. The results obtained in this research work clearly indicated the Pisum fulvum lectin could be a promising potential anticancer agent.

Reciprocal compatibility within the genus Pisum L. as studied in F1 hybrids: 2. Crosses involving P. fulvum Sibth. et Smith

Pisum fulvum Sibth. et Smith. (accession WL2140) was crossed, in both directions, with seven accessions representing other pea taxa: P. abyssinicum A. Br. (1 accession), P. sativum L. subsp. elatius (Bieb.) Schmalh. s.l. (5 accessions) and the cultivated pea, P. sativum L. subsp. sativum (1 accession). Efficiency of crosses (the average number of hybrid seeds per cross), pollen and seed fertility and general quantitative traits of reciprocal F1 hybrids were evaluated in a greenhouse experiment. Crossability with P. fulvum as the seed parent was very poor but at least some viable seeds were obtained in all crosses. F1 hybrids with accessions VIR320, 721 and CE1 (P. s. elatius) were very weak and produced 0–3 seeds; those with WL1238 (P. s. sativum) were variable in vigour and fertility; both reciprocal hybrids with JI1794 were small plants. Other hybrids were tall, vigorously branching but poorly fertile plants. In all F1 hybrids, pollen fertility did not exceed or scarcely exceeded 50% without differences between reciprocal hybrids except for the pair P. fulvum × P. s. sativum. Pollen of all hybrids contained micro-grains formed around chromosomes retarded in anaphase I. Seed fertility was low, with significant differences between reciprocal hybrids found only in the pair P. fulvum—JI1794. F1 hybrids between P. fulvum and peas of the evolutionary ‘lineage AC’ showed higher pollen and seed fertility than those with peas of the ‘lineage B’. The sum of evidence available suggests that P. fulvum does not differ from P. sativum by reciprocal translocations.

Determination of morphological variability of different pisum genotypes using principal component analysis

The aim of the study was to evaluate the variation among some Pisum genotypes using principal component analysis technique. The plant material covering wild pea accessions (Pisum fulvum L., P. abyssinicum L., P. sativum var. elatius), local varieties (P. sativum var. sativum L. and P. sativum var. arvense L.) and two commercial varieties were evaluated for 50 morphological traits. According to results, the first eleven principal component with Eigenvalues >1 contributed % 96.95 of the variability. The percentages of cumulative variation accounted for by each of the four principal component are 33.14%, 48.72%, 58.65%, and 66.88% respectively. Based on the principal coordinate analysis, five major groups were formed. In general, the diagram represented an obvious division between taxonomic groups except for P. sativum var. sativum and P. sativum var. arvense accessions.

Cryptic divergences in the genus Pisum L. (peas), as revealed by phylogenetic analysis of plastid genomes

Organellar genomes may shed light on complicated patterns of plant evolution at inter- and intraspecies level. Primary structure of plastid genomes sequenced in this study and taken from public databases was characterised and compared in 22 diverse, mostly wild representatives of the genus Pisum (peas). Phylogenetic trees reconstructed via Bayesian approach on the basis of entire plastid genomes resembled those reconstructed on the basis of a nuclear gene His5 coding for a minor histone H1 subtype. They reveal Pisum fulvum as an early divergence of the genus but do not support other taxonomical subdivisions. The positions of three accessions, classified as P. sativum subsp. elatius (the wild subspecies of the common pea), appeared quite unexpected. On the entire plastid genome tree, two accessions, from the Black Sea area of Turkey and Georgia, clustered with representatives of another species, P. fulvum, while the other, from Greece, was the first divergence of the P. sativum branch. We suppose these unusual plastid genomes to be ancient lineages ascending to a ‘missing link’ between P. fulvum and P. sativum, represented by accession Pe 013 from Turkey. Accessions with common pea appearance but deeply diverged plastids could occur through occasional crossing of diverged pea lines in the past and biparental plastid inheritance, both events being possible in peas.

A High-Density Integrated DArTseq SNP-Based Genetic Map of Pisum fulvum and Identification of QTLs Controlling Rust Resistance.

Pisum fulvum, a wild relative of pea is an important source of allelic diversity to improve the genetic resistance of cultivated species against fungal diseases of economic importance like the pea rust caused by Uromyces pisi. To unravel the genetic control underlying resistance to this fungal disease, a recombinant inbred line (RIL) population was generated from a cross between two P. fulvum accessions, IFPI3260 and IFPI3251, and genotyped using Diversity Arrays Technology. A total of 9,569 high-quality DArT-Seq and 8,514 SNPs markers were generated. Finally, a total of 12,058 markers were assembled into seven linkage groups, equivalent to the number of haploid chromosomes of P. fulvum and P. sativum. The newly constructed integrated genetic linkage map of P. fulvum covered an accumulated distance of 1,877.45 cM, an average density of 1.19 markers cM−1 and an average distance between adjacent markers of 1.85 cM. The composite interval mapping revealed three QTLs distributed over two linkage groups that were associated with the percentage of rust disease severity (DS%). QTLs UpDSII and UpDSIV were located in the LGs II and IV respectively and were consistently identified both in adult plants over 3 years at the field (Córdoba, Spain) and in seedling plants under controlled conditions. Whenever they were detected, their contribution to the total phenotypic variance varied between 19.8 and 29.2. A third QTL (UpDSIV.2) was also located in the LGIVand was environmentally specific as was only detected for DS % in seedlings under controlled conditions. It accounted more than 14% of the phenotypic variation studied. Taking together the data obtained in the study, it could be concluded that the expression of resistance to fungal diseases in P. fulvum originates from the resistant parent IFPI3260.

Wading Into the Gene Pool: Progress and Constraints Using Wild Species

Wading Into the Gene Pool: Progress and Constraints Using Wild Species

Drought Response and Genetic Diversity in Pisum fulvum, a Wild Relative of Domesticated Pea

Productivity of grain crops in semi‐arid environments is often affected by drought, which is likely to increase due to predicted climate changes. Wild pea (Pisum fulvum Sibth. & Smith, Pf) accessions sampled across its ecological amplitude in Israel (350–850 mm annual precipitation) were used to assess the genetic diversity for drought responses. We hypothesized that native species evolving under Eastern Mediterranean climate carry adaptive traits to cope with drought stress. Accessions were classified according to single‐nucleotide polymorphism variation pattern and habitat ecogeographic parameters. Significant differences were found between the accession groups, but grouping in both systems did not match. Subsequently, 52 Pf accessions and three domesticated pea (P. sativum L.) genotypes were evaluated during 2 yr under well‐watered (∼580 mm) and water‐limited (∼340 mm) treatments. Total dry matter, grain yield, harvest index, and average grain weight were higher in domesticated pea than wild Pf; however several Pf accessions exhibited lower drought susceptibility indices (i.e., greater stability across environments) than domesticated genotypes. Of special interest are a number of Pf genotypes in which low susceptibility to water stress was coupled with relatively high productivity. The sampling habitats of those low susceptibility–high productivity accessions are characterized by mild (400–530 mm) annual precipitation. Further sampling and evaluation of Pf from such locations may improve our understanding of pea drought adaptation and yield physiology.

Abyssinian pea (Lathyrus schaeferi Kosterin nom. nov. pro Pisum abyssinicum A. Br.) is a problematic taxon

The Abyssinian pea (Pisum abyssinicum A. Br.), concerned in this review, is known from Ethiopia and Yemen, where it is cultivated along with the common pea (Pisum sativum L. subsp. sativum). The continuously reproduced notion of its possible spontaneous occurrence in the wild ascends to suppositions made in the XIX century and is not based on any actual data. P. abyssinicum is of practical interest owing to its extra early ripening and resistance to bacterial blight. Morphologically it is very similar to P. sativum but its crossability with it is bad as either seed or pollen parent. Traditionally this reproductive barrier was associated with karyological differences. The Abyssinian pea karyotype is variable as 1–2 reciprocal translocations were reported. At the same time there are accessions not differing from the standard karyotype of P. sativum with respect to reciprocal translocations, yet their crossability with the latter is very low and the pollen fertility of F1 and F2 hybrids is lowered. Data were reported on influence of the region of Linkage Group III, containing a gene known to participate in the conflict of nucleus and plastids in remote crosses of peas, on the pollen fertility of hybrids with abyssinian pea. With their karyological variability, the known accessions of the Abyssinian pea are very close to each other genetically, as they diverged just about 4000 years ago. The presence of alleles of molecular markers common with Pisum fulvum Sibth. et Smith on the one hand and P. sativum L. subsp. elatius (Bieb.) Schmalh. on the other hand evidences in favour of an old hypotheses by L.I. Govorov that the Abyssinian pea originated from their spontaneous hybrid. This spontaneous cross may have taken place under cultivation, in Yemen or Afar Depression. A representative of P. sativum subsp. elatius was revealed, the F1 hybrids of which with the Abyssinian pea as a seed parent had fully fertile pollen. P. abyssinicum× P. fulvum crosses provide the best hybrid seed outcome among remote crosses conducted, so that P. abyssinicum can be used as a ‘bridge’ for gene introgression from P. fulvum to P. sativum. Rather a high evel of reproductive isolation of the Abyssinian pea from other representatives of the genus conforms the biological species concept, however the disposition of P. abyssinicum accessions as a small cluster among accessions of P. sativum subsp. elatius on molecular phylogeny reconstructions violates the phylogenetic species concept. Most authors assume the Abyssinian pea as a species, Pisum abyssinicum, some as a subspecies, P. sativum subsp. abyssinicum (A. Br.) Berger. Perhaps it would be most correct to consider it as a hybridogenic species. Because of the recent subsuming of the genus Pisum L. into the genus Lathyrus and with respect to the existing name Lathyrus abyssinicus A. Br. (a synonym of L. sativus L.), the Abyssinian pea is given a new name Lathyrus schaeferi (A. Braun) Kosterin nomen novum pro Pisum abyssinicum A. Braun), in honour of Hanno Schaefer, who substantiated the revision of tribe Fabeae by molecular reconstruction of its phylogeny. New combinations of Lathyrus sectio Pisum (L.) Kosterin combinatio nova and Lathurus fulvus (Sibthrop et Smith) Kosterin combinatio nova are proposed.

Identification of QTLs Associated with Improved Resistance to Ascochyta Blight in an Interspecific Pea Recombinant Inbred Line Population

Ascochyta blight of pea (Pisum sp.), caused by Peyronellaea pinodes, often results in serious yield losses. Some accessions of Pisum fulvum Sibth. & Sm. previously showed high levels of resistance and could be used as sources of new resistance genes. The objectives of this study were to develop a single nucleotide polymorphism (SNP)‐based linkage map and identify genomic regions associated with Ascochyta blight resistance. A population (PR‐19) consisting of 144 recombinant inbred lines (RILs) developed from a cross between P651 (P. fulvum) and Alfetta (Pisum sativum L.) was used. These RILs were evaluated for Ascochyta blight resistance under field conditions in Saskatchewan, as well as under greenhouse conditions. The RILs were genotyped using an Illumina GoldenGate array panel of 1536 SNPs. A wide range of variation was observed in Ascochyta blight scores and other agronomic traits. Disease scores were positively correlated (P < 0.001) with lodging and were negatively correlated (P < 0.001) with days to flower, plant height, days to maturity, and grain yield. A total of 733 SNP markers were assigned to six linkage groups covering 682.1 cM of the pea genome. Nine quantitative trait loci (QTLs) were identified for Ascochyta blight resistance, which individually explained 7.5 to 28% of the total phenotypic variation. In addition, five QTLs each were identified for plant height, days to maturity, and grain yield, four QTLs for days to flower, and two QTLs for lodging. The QTL abIII‐1 was consistent across locations and years, whereas abI‐IV‐2 was significant at both locations in 2014. These QTLs can be utilized for development of molecular markers associated with Ascochyta blight resistance.

The Temperature Response and Aggressiveness of Peyronellaea pinodes Isolates Originating from Wild and Domesticated Pisum sp. in Israel.

Domesticated pea fields are grown in relatively close proximity to wild pea species in Israel. Despite the major role attributed to ascochyta blight in causing yield losses in domesticated pea, very limited information is available on the pathogens prevailing in natural ecosystems. The objectives of this study were (i) to identify the species causing ascochyta blight symptoms on leaves, stems, and petioles of domesticated pea and wild Pisum plants in Israel, and (ii) to quantify the temperature response(s) and aggressiveness of such pathogens originating from Pisum plants growing in sympatric and allopatric contexts. Eighteen fungal isolates were examined and identified; three of them were sampled from Pisum sativum, 11 from Pisum fulvum, and four from Pisum elatius. All isolates were identified as Peyronellaea pinodes. Spore germination and mycelial growth took place over a wide range of temperatures, the lower and upper cardinal temperatures being 2 to 9 and 33 to 38°C, respectively; the optimal temperatures ranged from 22 to 26°C. At an optimal temperature, disease severity was significantly higher for plants maintained under moist conditions for 24 h postinoculation than for those exposed to humidity for 5 or 10 h. Analyses of the data revealed that temperature responses, spore germination rates, and aggressiveness of isolates sampled from domesticated pea plants did not differ from those of isolates sampled from adjacent or distant wild populations. Host specificity was not observed. These observations suggest that Israel may be inhabited by a single metapopulation of P. pinodes.